Reversi Board
Reversi is a two-player territory game. Place a disc only where it brackets at least one opposing disc in a straight horizontal, vertical or diagonal line; every bracketed line flips. A player with no legal square must pass. When neither side can move, two consecutive forced passes end the game and the larger disc count wins. The local opponent uses a small deterministic corner/edge/flip rule, not deep strategy or an engine.
Key features
- Standard 8×8 four-disc opening and exact eight-direction line captures
- Legal-square markers, illegal-move rejection and forced pass only when no move exists
- Two-pass game end with black/white/empty counts and win/draw result
- Two-person play or deterministic browser-local rule-based White opponent
- Roving keyboard focus, touch controls, complete move/pass log and undo
How to use
- Choose two-person or local-computer play; Black begins from the standard four-disc board.
- Select a marked legal square to bracket and flip one or more opponent discs; use arrow keys to navigate the board.
- If a player has no legal square, use Pass; in computer mode White takes its move or passes automatically.
- After both sides pass consecutively, compare disc counts; use Undo or New game to review or start over.
Use cases
- Learn why a move can capture along several directions at once
- Play a short shared-device strategy match with explicit turn and score states
- Practice identifying legal squares and forced passes against a predictable opponent
Frequently asked questions
Which squares are legal?
An empty square is legal only if at least one straight direction runs through one or more opposing discs and ends at one of your own. All qualifying directions flip.
Can I pass to avoid a move?
No. Passing is required and allowed only when the active player has no legal square.
When does the game finish?
Two consecutive forced passes end the game. This also covers a full board. The higher disc count wins; equal counts are a draw.
How strong is the computer?
It is deliberately simple and deterministic: corners first, then edges, then the number of flips, with square order as a tie-breaker. It does not search future turns.
What does Undo do against the computer?
It returns to the start of the previous human turn, reversing the computer reply as well if one occurred.
Privacy
The match and move record stay in this browser tab. The computer chooses moves locally; no game state is sent to a server and no account or external engine is used.
Comments & questions